Valve for fluid ejector

ABSTRACT

A valve assembly for a dental suction system. The valve assembly includes a valve body having an inlet, an outlet and a fluid flow path extending between the inlet and the outlet. The valve assembly also includes a valve plug positioned at least partially within the valve body and including a through-passage. The valve plug is rotatable relative to the valve body to selectively alter a flow of fluid along the fluid flow path. The fluid flow path exhibits a varied cross-sectional area along a length of the fluid flow path.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/375,819 filed Aug. 16, 2016, and titled “Valve for Fluid Injector,”the disclosure of which is hereby incorporated in its entirety by thisreference.

TECHNICAL FIELD

The present disclosure generally relates to suctioning devices, and moreparticularly to valves associated with medical and dental suctioningdevices.

BACKGROUND

Cross-contamination between patients, for example, dental patients, canoccur when suctioning devices attached to vacuum lines are used toremove various bodily and/or externally introduced fluids. Although thedisposable distal ends of these devices typically are changed betweenpatients, the vacuum lines employed, along with various valves,typically are not changed. Saliva, blood and other contaminants passfrom the distal end into the vacuum line, where they can remain untilarrival of the next patient. When a new distal end is inserted onto thevacuum line for a new patient, contaminants from the previous patientcan backflow from the vacuum line into the distal end and enter thepatient's mouth, for example. Clearly, it is desirable to avoid such asituation.

Some suction devices may include suction lines having vacuum-releaseapertures through a tubular sidewall of a saliva ejector tip. If apatient closes his or her lips around the tip, the vacuum-releaseaperture is said to prevent creation of a temporary high vacuum in thepatient's mouth; the aperture also likely prevents stoppage of airand/or fluid, at least between the aperture and the rest of the system.Other types of suction devices rely on a “tortuous path” within thedevice to substantially prevent backflow of bacteria.

However, due to various flow dynamics, including boundary layers formedaround an internal circumference of many currently used suctioningdevices, it is possible for a “bio-film” to be created along internalsurfaces of the suction device, allowing saliva, blood and othercontaminants to flow by gravity, for example, from a main vacuum system,through saliva ejector assemblies and into the mouths of patients.

Additionally, in many practices, the on/off valve of a suction device is“permanent” in that it is not conventionally replaced after use on asingle patient. Rather, the same on/off valve is used with multiplepatients creating the same concerns as outlined above with regard tocontaminants flowing by gravity through a system and, eventually, intothe mouths of patients.

As such, there is a continuing desire in the industry to provide valvesand suction devices that minimize, if not eliminate, the potentialexposure of patients to contaminants.

DISCLOSURE OF THE INVENTION

One aspect of the present disclosure relates to a valve assembly for adental suction system. The valve assembly includes a valve body havingan inlet, an outlet and a fluid flow path extending between the inletand the outlet. The valve assembly also includes a valve plug positionedat least partially within the valve body and including athrough-passage. The valve plug is rotatable relative to the valve bodyto selectively alter a flow of fluid along the fluid flow path. Thefluid flow path exhibits a varied cross-sectional area along a length ofthe fluid flow path.

The valve assembly may also provide, when the through-passage is alignedwith the fluid flow path to permit fluid flow through the valve body,the fluid flow path having a first portion having a first centerline anda second portion having a second centerline, wherein the firstcenterline is offset from the second centerline. The through-passage mayinclude a first opening on a first side of the valve plug, a secondopening on a second side of the valve plug, and a ramped surfaceextending at least partially between the first opening and the secondopening. The first opening may have a semicircular geometry, and thesecond opening may have a semicircular geometry. The valve plug may forma seal with the valve body along a proximal side of the valve plug whenthe valve plug is in a closed position. The valve assembly may includeat least one backflow prevention device disposed in the fluid flow path.The at least one backflow prevention device may be positioned betweenthe valve plug and the inlet of the valve body. The at least onebackflow prevention device may be positioned between the valve plug andthe outlet of the valve body. The at least one backflow preventiondevice may include a flexible and resilient material, and be movablerelative to the valve body to control fluid flow through the fluid flowpath independent of operation of the valve plug.

Another aspect of the present disclosure relates to a valve assembly fora dental suction system. The valve assembly includes a valve body, avalve plug, and a backflow prevention device. The valve body has aninlet, an outlet and a fluid flow path extending between the inlet andthe outlet. The valve plug is positioned at least partially within thevalve body and includes a through-passage. The valve body isdisplaceable relative to the valve body to selectively alter a flow offluid along the fluid flow path. The backflow prevention device isdisposed in the fluid flow path between the valve plug and the inlet ofthe valve body or between the valve plug and the outlet of the valvebody. The backflow prevention device is movable between open and closedpositions to control fluid flow through the fluid flow path independentof operation of the valve plug.

The backflow prevention device may include a resilient, flexible memberhaving a peripheral portion fixed relative to the valve body. The fluidflow path may be configured such that the fluid flow path includes afirst portion having a first centerline distal of the valve plug and asecond portion having a second centerline as proximal of the valve plug,wherein the first centerline is offset from the second centerline. Thevalve plug may be rotatable between open and closed positions. The valveplug may sealingly engage the valve body when the valve plug is in aclosed position to block fluid flow through the fluid flow path.

A further aspect of the present disclosure relates to a valve assemblyfor a dental suction system. The valve assembly includes first andsecond valve bodies, a backflow prevention device, and a valve plug. Thefirst valve body includes a first inlet, a first outlet, and a firstfluid flow path extending between the first inlet and the first outlet.The second valve body includes a second inlet, a second outlet, and asecond fluid flow path extending between the second inlet and the secondoutlet. The backflow prevention device is captured between the first andsecond valve bodies, and is movable to control fluid flow along at leastone of the first and second fluid flow paths. The valve plug ispositioned at least partially within the first valve body and includes athrough-passage. The valve body is displaceable relative to the valvebody to selectively alter a flow of fluid along at least one of thefirst and second fluid flow paths.

The first fluid flow path may include a first portion having a firstcenterline distal of the valve plug and the second fluid flow path mayinclude a second portion having a second centerline proximal of thevalve plug, wherein the first centerline is offset from the secondcenterline. The backflow prevention device may be positioned between thevalve plug and the first inlet. The backflow prevention device may bepositioned between the valve plug and the first outlet. At least one ofthe first and second valve bodies may include an alignment featureconfigured to align the first valve body relative to the second valvebody in a predetermined rotated position. The valve plug may form a sealwith the second valve body along a proximal side of the valve plug whenthe valve plug is in a closed position.

The above summary is not intended to describe each disclosed embodimentor every implementation of the inventive aspects disclosed herein.Figures in the detailed description that follow more particularlydescribe features that are examples of how certain inventive aspects maybe practiced. While certain embodiments are illustrated and described,it will be appreciated that disclosure is not limited to suchembodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other advantages of the invention will become apparentupon reading the following detailed description and upon reference tothe drawings in which:

FIG. 1 is a perspective view of a suction assembly according to anembodiment of the present disclosure;

FIG. 2 is an exploded perspective view of a valve assembly according tothe present disclosure;

FIG. 3A is a cross-sectional view of the valve assembly shown in FIG. 2with the valve in a closed position;

FIG. 3B is another cross-sectional view of the valve assembly shown inFIG. 3A;

FIG. 3C is a cross-sectional view of the valve assembly shown in FIG. 2with the valve in an open position;

FIG. 3D is another cross-sectional view of the valve assembly shown inFIG. 3C;

FIG. 4 is a cross-sectional view of another valve assembly embodiment inaccordance with the present disclosure;

FIG. 5 is an exploded, cross-sectional perspective view of the valveassembly shown in FIG. 2;

FIG. 6 is a cross-sectional perspective view of the valve assembly shownin FIG. 2;

FIG. 7 is a cross-sectional perspective view of a portion of the valveassembly shown in FIG. 2;

FIGS. 8A-8C are various views of a component of the valve assembly shownin FIG. 2;

FIGS. 9A and 9B are perspective views of a portion of a valve assemblyin an open position in accordance with the present disclosure;

FIGS. 9C and 9D are perspective views of the portion of a valve assemblyshown in FIGS. 9A and 9B with the valve in a closed position;

FIGS. 9E and 9F are exploded perspective views of the portion of a valveassembly shown in FIGS. 9A and 9B;

FIGS. 9G and 9H are cross-sectional perspective views of the portion ofa valve assembly shown in FIGS. 9A and 9B with the valve in closed andopen positions, respectively;

FIGS. 10A-C show the portion of a valve assembly shown in FIGS. 9A and9B with the valve member an open position;

FIGS. 11A-C show the portion of a valve assembly shown in FIGS. 9A and9B with the valve member in a closed position;

FIGS. 12A-12C are side and top views of a valve device according to anembodiment of the present disclosure; and

FIG. 13A-13C are side and top views of a valve device according to anembodiment of the present disclosure.

BEST MODE(S) FOR CARRYING OUT THE INVENTION

Various embodiments will be described in detail with reference to thedrawings, wherein like reference numerals represent like parts andassemblies throughout the several views. Reference to variousembodiments does not limit the scope of the claims attached hereto.Additionally, any examples set forth in this specification are notintended to be limiting and merely set forth some of the many possibleembodiments for the appended claims.

The following discussion is intended to provide a brief, generaldescription of a suitable environment in which the invention may beimplemented. Although not required, the invention will be described inthe general context of vacuum suction devices, for example, a dentalsaliva ejector device. The structure, creation, and use of some exampledental fluid ejector devices and various components or subassemblies ofcomponents of such fluid ejectors are described hereinafter.

The example embodiments disclosed herein have wide application to anumber of medical procedures and environments. Suction is often used indental applications, as described above. Suctioning devices are alsotypically used to drain fluid and remove blood from many surgicalenvironments, aid in respiration, and aid in a number of other medicaland surgical procedures. Additionally, suctioning devices in whichcross-contamination is undesirable are used in non-medical andnon-surgical environments, such as in some types of liquid soapdispensers where preventing backflow of a fluid is required, and in thefood service industry where various ingredients or food products mustremain separated. Therefore, while most of the embodiments describedwith reference to the attached figures are directed to dental devicesand applications, many other applications and related embodiments areenvisioned.

An example suction assembly 100 is shown in FIG. 1. The suction assembly100 includes an ejector tube assembly 102, an ON/OFF valve assembly 104and a vacuum hose 106. The vacuum hose may be coupled with a vacuumsource (not shown) as will be appreciated by those of ordinary skill inthe art. While not explicitly shown in FIG. 1, the suction assembly 100may include other components including, for example, and a cover memberextending over the ON/OFF valve assembly 104 and a portion of the vacuumhose 106. Additionally, in some embodiments, a backflow preventionassembly may be coupled, for example, between the ON/OFF valve assembly104 and the ejector tube assembly 102, or between the ON/OFF valveassembly 104 and the vacuum hose 106. A backflow prevention assembly maybe integrated into the ON/OFF valve assembly 104. Some non-limitingexamples of backflow prevention assemblies are described in U.S. Pat.No. 8,714,200, issued May 6, 2014, to Bushman et al., and U.S. Pat. No.6,203,321, issued Mar. 20, 2001, to Helmer et al., the disclosures ofeach of which are incorporated herein in their entireties by thisreference. In other embodiments, such as shall be described in furtherdetail below, a backflow prevention structure or assembly may beincorporated into the ON/OFF valve assembly 104 in a variety of waysand/or locations, as will be described herein.

FIG. 2 is a perspective view of an ON/OFF valve assembly 104 which maybe used in a suction assembly such as the suction assembly 100 depictedin FIG. 1, for example. The ON/OFF valve assembly 104 includes a housingor body assembly 110 having a distal end 112 (which may also be referredto as an inlet) configured for connection with an ejector tube 102, orother similar device, and a proximal end 114 (which may also be referredto as an outlet) configured for connection with a vacuum hose 106. Asindicated by directional arrow 116, flow is intended to pass through thevalve from the distal end 112 to the proximal end 114. The body assembly110 includes a distal portion 150, which defines the distal end 112, anda proximal portion 152, which defines the proximal end 114. The distaland proximal portions 150, 152 may include alignment features to providea predetermined rotational alignment of the portions 150, 152 whenconnected together. For example, the distal portion 150 may include analignment groove (see FIGS. 2 and 5) that mates with an alignmentprotrusion 156 of the proximal portion 152 (see FIGS. 5 and 7).

The ON/OFF valve assembly 104 also includes a rotary valve plug 120coupled with a lever 122. The valve plug 120 is at least partiallydisposed within the valve body 110 and is configured to rotate relativeto the valve body 110 about an axis 124. Rotation of the valve plug 120about the axis 124 may be accomplished by a user applying a force (e.g.,with their thumb) to the lever 122. The plug includes an openingtherethrough (as discussed in further detail below) such that whenrotated to a first position (e.g., an “OFF” position), fluid flow fromthe distal end 112 to the proximal end 114 is interrupted, but whenrotated to a second position (e.g., an “ON” position), fluid flow fromthe distal end 112 to the proximal end 114 is permitted.

Referring to both FIGS. 1 and 2, during use of the suction assembly 100,suction is applied by way of a vacuum source coupled with the vacuumhose 106. An operator actuates the valve plug 120, moving it from an OFFposition to an ON position by way of the associated lever 122, and theend of the ejector tube assembly 102 is placed adjacent an area wherefluid removal is required (e.g., in a patient's mouth to remove saliva).When suction is no longer required, the operator again actuates thevalve plug 120, moving it from the ON position to the OFF position, andplaces the suction assembly 100 in a temporary holding location untilsuction is again needed for a given patient.

After the suction assembly 100 is finished being used for a givenpatient, the ejector tube assembly 102 and the ON/OFF valve assembly 104may be removed from the vacuum hose and disposed of. A new ON/OFF valveassembly 104 and a new ejector tube assembly 102 may be coupled to thevacuum hose for use with each new patient. As will be described infurther detail below, various components of the ON/OFF valve assembly104 may be formed of relatively inexpensive materials (e.g., polymericmaterials) and formed using relatively inexpensive manufacturingprocesses (e.g., molding) to provide inexpensive, disposable products inan effort to maintain the highest possible sterility in a dental ormedical environment. In other embodiments, the ON/OFF valve assembly 104may comprise different materials and/or different manufacturingprocesses to provide a more expensive, multi-use product that can becleaned and reused.

Referring now to FIGS. 3A-3D, several cross-sectional views are shown ofan ON/OFF valve assembly 104 according to an embodiment of the presentdisclosure, such as the embodiment shown in FIG. 2. As previously noted,the valve assembly 104 may include a valve body 110 having a distal end112 and a proximal end 114. In some embodiments, the valve body may be asingle, substantially homogenous structure. In other embodiments, thevalve body 110 may be formed of multiple body portions 150, 152 such asseen in FIGS. 3A-3D. A valve plug 120 is at least partially disposedwithin the valve body 110 and configured to rotate about a defined axis124. An opening or a through-passage 130 is formed in the valve plugsuch that when the valve plug 120 is in an “ON” position, thethrough-passage 130 is substantially aligned with a flow path 118between the distal and proximal ends 112, 114 of the valve body 110 (asshown in FIGS. 3A-3B), enabling fluid flow through the valve assembly104. When the valve body 110 is rotated to an “OFF” position, thethrough-passage 130 is placed at an angle relative to the flow pathbetween the distal and proximal ends of the valve body 110 such thatfluid flow is interrupted or inhibited (as shown in FIGS. 3C-3D).

The valve plug 120, while rotatable relative to the valve body 110, maybe sealed relative to the valve body 110 so that fluid does not leakbetween the valve body 110 and the valve plug 120. For example, in oneembodiment, the valve plug 120 may extend through an opening 132 formedin the valve body 110. A ridge or lip 134 and groove 136, which areformed on the valve plug 120 may cooperatively engage an aperture rim155 formed in the valve body 110 at an outer valve aperture 157 to forma fluid-tight seal therebetween. A detailed view of the connection pointbetween the valve body 110 and the valve plug 120 is shown in FIG. 7.The sealed connection point between the valve body 110 and the valveplug 120 may be located at a side of the valve body 110 opposite theside where the valve plug 120 is inserted into the opening 132 of thevalve body 110, and opposite the side of the valve plug 120 where thelever 122 is connected. A inner valve aperture 153 is provided alongthat surface of body portion 152 where the valve plug 120 is inserted(see FIG. 3B).

In other embodiments, the lip/groove and rim arrangement may be reversedbetween the valve body 110 and the valve plug 120. In yet otherembodiments, corresponding grooves may be formed in each of the valvebody 110 and the valve plug 120, and an O-ring or other seal member maybe disposed within the corresponding grooves to provide a desired sealtherebetween. In yet further embodiments, depending on the level ofsuction being drawn through the valve assembly 104, an closeinterference fit between the valve body 110 and the valve plug 120 maybe sufficient to provide a seal therebetween. In some embodiments, theconnection provided between the valve body 110 and the valve plug 120may be a snap-fit connection. The connection between the valve body 110and the valve plug 120 may be a releasable connection to provideassembly and disassembly of the valve assembly 104 as desired. In otherembodiments, the connection may be a permanent connection such that thedamage to the valve assembly 104 would result from attempting todisconnect the valve plug 120 from the valve body 110.

The valve assembly 104 may also incorporate a backflow prevention device140. The backflow prevention device 140 may operate as a check valve tohelp prevent fluids from draining or flowing in the direction toward thedistal end 112 of the valve assembly 104 regardless of the operationalposition of the valve plug 120 (e.g., even if the valve plug 120 may bein an “OFF” position). The backflow prevention device 140 may preventdrainage or backflow of fluids in the event that vacuum is lost whilethe valve plug 120 is in the “ON” position.

In one embodiment, the backflow prevention device 140 may include aflexible and resilient member 142 having a first portion fixed relativeto the valve body 110 and a second portion that is displaceable relativeto the valve body 110. Thus, for example, when the valve plug is in the“ON” position and suction is applied through the valve assembly 104, theflexible nature of the member 142 enables a portion to be displacedrelative to the valve body 110 (as shown in FIG. 3C) to enable flow inthe direction indicated by arrow 116. However, the resilient nature ofthe member 142 causes it to automatically return to a “closed” statewhen suction is not being applied to the valve assembly 104 (and/or whenthe valve plug 120 is in the “OFF” position—see FIG. 3A). The member142, therefore, acts as a check valve for the valve assembly 104. Such abackflow prevention device 140 may be constructed such as described inpreviously incorporated U.S. Pat. No. 8,714,200. Of course, other typesof backflow prevention devices may be incorporated into valve assembly104 if desired.

The resilient member 142 of the backflow prevention device 140 may becaptured between the distal and proximal portions 150, 152 of the bodyassembly 110. The resilient member 142 may be held at a location insidean outer periphery of the resilient member 142, such as radially in froman outer circumferential edge of the resilient member 142, as shown inat least FIGS. 3A and 3C. The resilient member 142 may be positionedwithin a valve seat 158 formed in at least one of the distal andproximal portion 150, 152 of the body assembly 110. FIGS. 3C and 5 shownan example valve seat 158 formed in the distal portion 152. Theresilient member 142 may contact a surface of the valve seat 158 to forma fluid-tight seal that prevents backflow of fluids when the resilientmember 142 is in the closed position shown in, for example, FIGS. 3A and6.

At least one of the distal and proximal portions 150, 152 may includeone or more valve retention features 159 to assist with securing theresilient member 142 in place. FIG. 5 shows separate valve retentionfeatures 159 positioned on each of the distal and proximal portions 150,152. FIGS. 2 and 5 show a valve retention feature 143 on the distalportion 150. FIGS. 5, 7 and 9A-9B show a valve retention feature 159 onthe proximal portion 152. The valve retention features 159 may be sizedand arranged to interface with a recess 143 of the resilient member 142.The recess 143 may be positioned radially inward from a rim 145 of theresilient member 142 (see FIGS. 2, 5 and 6).

In the embodiment shown in FIGS. 3A-3D, the backflow prevention device140 is placed upstream of the valve plug 120 (e.g., between the distalend 112 of the housing and the valve plug 120 in the specific embodimentshown in FIGS. 3A-3D). Such an embodiment may provide the advantage ofcontaminants that may have reached the valve plug 120 (e.g., from thevacuum hose 106) being blocked from possibly draining beyond thebackflow prevention valve in certain situations. FIG. 4 shows a valveassembly 104-a having substantially similar components as the valveassembly 104 shown in FIGS. 3A-3D, except that the backflow preventiondevice 140 is positioned down-stream from the valve plug 120. Such anembodiment may provide the advantage of helping to prevent contaminationfrom a vacuum hose ever reaching the valve plug 120 in certaincircumstances. While not shown, in other embodiments, a valve assemblymay include multiple backflow prevention devices including one or morepositioned upstream of the valve plug 120 and one or more positioneddownstream of the valve plug 120. In yet other embodiments, the valveassembly 104 may not include any backflow prevention devices.

FIG. 5 is an exploded cross-sectional view of the valve assembly 104depicted in FIGS. 3A-3D, showing a two-piece valve body 110 (e.g.,distal portion 150 and proximal portion 152) that may be used inconjunction with certain backflow prevention devices 140. Additionally,FIG. 5 shows the opening 132 through which a portion of the valve plug120 extends (lever 122 of the valve plug 120 not shown in FIG. 5). Inone embodiment, a backflow prevention member 142 may be positionedbetween the distal portion 150 and proximal portion 152 of the valvebody 110, with a portion of the backflow prevention member's peripheraledge being clamped between the two portions 150, 152 such as describedin previously incorporated U.S. Pat. No. 8,714,200.

Referring to FIGS. 6 and 7, cross-sectional views of an ON/OFF valveassembly 104 are shown (with certain portions removed in FIG. 7 forpurposes of clarity). FIGS. 6 and 7 show the through-passage 130 of thevalve plug 120 in further detail. While in some embodiments, thethrough-passage 130 may include a through-bore having a substantiallyconstant cross section, the through-passage 130 depicted in FIGS. 6 and7 includes a through-bore that may have a constant cross-sectional areaalong the intended path of fluid flow (as taken perpendicularly to theintended path of fluid flow). In other embodiments, the through-passage130 may include a variable cross-section resulting from, for example, aramp portion extending along at least a portion of the through-passage130 such that an opening 162 on one side of the valve plug 120 exhibitsa larger cross-sectional area than an opening 164 on the opposing sideof the valve plug 120 (e.g., see embodiment shown in FIGS. 10A-11C).

In some embodiments, the flow path 118 through the body assembly 110 mayhave variable cross-sectional size along its length between the distaland proximal ends 112, 114. The flow path may include, for example, aramp portion 159. The ramp portion 159 may be positioned at a proximalend of the valve plug 120 and provide a transition to an outlet opening164 of the valve plug 120 (see FIG. 3C). Thus, in the embodimentsdepicted, the downstream outlet opening at proximal end 114 may exhibita larger cross-sectional area than does other portions of the flow path118, including a portion of the flow path defined by the valve plug 120when in the “ON” position. Referring to FIG. 3A, a portion of the flowpath 118 upstream of the valve plug 120 may have a height H1 (e.g., adiameter), and a portion of the flow path 118 downstream of the valveplug 120 may have a height H2, which is greater than the height H1. Sucha configuration may provide various advantages including, for example, ashorter “throw” of the valve plug being required between the ON and OFFpositions. In other words, the change in cross-sectional area along thelength of the through-passage 130 may result in the valve plug 120rotating through a smaller angle of rotation relative to the valve body110 between the ON and the OFF positions.

FIGS. 8A-8D include various views of a valve plug 120 according to anembodiment of the disclosure, including a through-passage 130 andopenings 162, 164 (such as described above). In one particularembodiment, such as best seen in FIG. 8C, both the inlet opening 162 andthe outlet opening 164 of the through-passage 130 may be semi-circularin geometry. However, other geometries are also contemplated and theexamples shown in FIGS. 8A-8D are not to be considered limiting. It isalso noted that the valve plug 120, as shown in FIGS. 8A-8D, may includea body portion 170 that is substantially cylindrical. However, the bodyportion 170 may exhibit other geometries including, for example,conical, frustoconical, spherical, semispherical, etc.

FIGS. 8A-8D also show the lip 134 formed on a portion of the valve plug120 and circumscribing the perimeter of the body portion 170. A groove136 may be formed adjacent to the lip 134 in certain embodiments. It isalso noted that, in some embodiments, a second lip may be formed on thevalve body such that at least one lip is positioned on opposite sides ofthe through-passage 130 in a spaced apart manner along the axis ofrotation 124 (see FIG. 2) of the valve plug 120. In yet otherembodiments, a single lip may be formed at a different location on thebody portion 170 of the valve plug 120 (e.g., on the opposite side ofthe through passage than is shown in FIGS. 8A-8D along the axis ofrotation 124). It is noted that the valve plug 120 is also depictedhaving a surface 172 formed on a peripheral surface at a locationopposite the lever 122. In some embodiments, the surface 172 may engagean cooperative internal surface formed in the valve body 110 to helpalign the valve plug 120 within the valve body 110. In otherembodiments, the valve plug 120 may include a radius, chamfer or othersurface feature formed in or in place of the surface 172, or may simplyinclude a direct angular transition from one surface to another withouta transition of a chamfer or radius.

FIGS. 3A, 5 and 7 show the valve plug 120 rotated into a closed or “OFF”position. In the closed position, a rear sealing surface 160 of thevalve plug 120 is arranged at a proximal or rear side of the valve plug120 to contact a sealing surface 194 of the valve body portion 152 toform a seal therebetween. Positioning this sealing interface at aproximal or rear side (e.g., an “exit” side) of the valve plug 120 whenthe valve plug 120 is rotated into a closed position may provideadvantages related to creating and maintaining the sealing when thevalve plug 120 is in the closed or “OFF” position. One objective of thedesign shown in FIGS. 3A-3D is to seal against the exit side of thevalve body rather than the inlet side (e.g., see embodiment shown inFIGS. 10A-11C). When sealing against the exit side via the interfacebetween rear sealing surface 160 of the valve plug 120 and the sealingsurface 194 of the valve body portion 152 as provided by the embodimentof FIGS. 3A-3D, the valve plug 120 only has to seal around the exit ofthe valve plug 120 and not also around the rotation axis on each side ofthe valve plug 120. In contrast, the embodiment of FIGS. 10A-11C, whichprovides a seal between the valve plug and the valve body at an entranceof the valve plug when the valve plug is rotated into a closed position,may also require sealing between the valve body and the valve plug alongthe rotation axis of the valve plug.

Referring now to FIGS. 9A-9D, a portion of a valve assembly 104 is shownaccording to an embodiment of the present disclosure. FIGS. 9A and 9Bshow the valve plug 120-a placed in an “ON” position, while FIGS. 9C and9D show the valve plug 120-a rotated to an “OFF” position. In the “OFF”position, the through-passage 130 is positioned relative to the flowpath between inlet and outlet ends of body portion 152-a of valve body110 so as to impede fluid flow through the valve body 110.

As illustrate in FIGS. 10B and 10C, the through-passage 130 of valveplug 120 may be configured to exhibit a varied cross-sectional areaalong a length of its flow path. The through-passage 130 may be definedin part by a ramp surface 166. In some embodiments, such a constructionmay result in offset centerlines 190, 192 of the flow path passingthrough the valve body 110. For example, as seen in FIG. 10B, the heightH1 of the opening leading into the through-passage 130 may besubstantially smaller than the height H2 of the opening leading out ofthe through-passage 130. The centerlines 190, 192 may be concentric andpositioned about a common plane, as seen in the top view of FIG. 9B.Generally, the flow path through the body portion 152-a has a centerline190 leading into the through-passage 130 which is offset from thecenterline 192 of a flow path leaving the through-passage 130.

In addition to providing a short throw-length for rotating the valveplug 120 between ON and OFF, the offset arrangement shown in FIG. 10Bmay also provide the valve body 110 with one or more valve retentionfeatures 159 that may be used to abut and clamp a peripheral portion ofa resilient member 142 of a backflow prevention device 140 such as hasbeen previously discussed.

FIGS. 11A-11C show the portion of valve assembly 104 shown in FIGS. 9Cand 9D with the valve plug 120-a rotated into a closed or “OFF”position. In the closed position, a front sealing surface 160-a isarranged at a distal or front side (e.g., an entrance side) of the valveplug 120-a to contact a sealing surface 194 of the valve body portion152-a at the entrance side of the valve plug 120-a to form a sealtherebetween. The embodiment of FIGS. 10A-11C may also provide a sealbetween the valve plug 120-a and the valve body portion 152-A along arotation axis of the valve plug 120-a.

Referring to FIGS. 12A-12C, another embodiment of a valve assembly 200is shown. FIGS. 12A and 12C are side views of a the valve assembly 200while FIG. 1w B is a top view of the valve assembly 200. The valveassembly 200 includes a valve body 202 having an inlet 204 and an outlet206, and a valve gate 208 configured to slide relative to the valve bodyin a direction that is at an angle (e.g., perpendicular to) the flowpath between the inlet 204 and the outlet 206. As seen in FIG. 12B, thegate 208 may be configured as a rectangular plate member. The gate 208may slide between an ON position, wherein a through passage 210 isaligned with the flow path of the valve body 202 (see FIG. 12A) and anOFF position wherein the through-passage is not aligned with the flowpath and, instead, fluid flow is blocked by the gate 208 from flowingbetween the inlet 204 and the outlet 206. In some embodiments, the valveassembly 200 may also include a backflow prevention device, such as aone way backflow prevention member 212 as has been discussed above. Aswith other embodiments, while FIGS. 12A and 12C show a backflowprevention member 212 positioned upstream of the gate 208, it may alsobe positioned downstream of the gate, or a plurality of backflowprevention members 212 may be used on either or both sides of the gate208.

Referring to FIGS. 13A-13C, another embodiment of a valve assembly 220is shown. FIGS. 13A and 13C are side views of a the valve assembly 220while FIG. 13B is a top view of the valve assembly 220. The valveassembly 220 includes a valve body 222 having an inlet 224 and an outlet226, and a slidable valve plug 228 configured to slide relative to thevalve body 222 in a direction that is at an angle (e.g., perpendicularto) the flow path between the inlet 224 and the outlet 226. As seen inFIG. 13B, the plug 228 may be configured as a cylindrical member. Theplug 228 may slide between an ON position, wherein a through-passage 230is aligned with the flow path of the valve body 222 (see FIG. 13A) andan OFF position wherein the through-passage 230 is not aligned with theflow path and, instead, the plug 228 blocks fluid from flowing betweenthe inlet 224 and the outlet 226. In some embodiments, the valveassembly 220 may also include a backflow prevention device, such as aone way backflow prevention member 232 as has been discussed above. Aswith other embodiments, while FIGS. 13A and 13C show a backflowprevention member 232 positioned upstream of the plug 228, it may alsobe positioned downstream of the plug 228. In other embodiments, aplurality of backflow prevention members 232 may be used on either orboth sides of the plug 228.

While the invention may be susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein. Forexample, components, features or aspects of one described embodiment maybe combined with components, features or aspects of other embodimentswithout limitation. However, it should be understood that the inventionis not intended to be limited to the particular forms disclosed. Rather,the invention includes all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as defined by thefollowing appended claims.

What is claimed is:
 1. A valve assembly for a dental suction system,comprising: a valve body having an inlet, an outlet and a fluid flowpath extending between the inlet and the outlet; a valve plug positionedat least partially within the valve body, the valve plug including athrough-passage, the valve plug being rotatable relative to the valvebody to selectively alter a flow of fluid along the fluid flow path,wherein the fluid flow path exhibits a varied cross-sectional area alonga length of the fluid flow path.
 2. The valve assembly of claim 1,wherein, when the through-passage is aligned with the fluid flow path topermit fluid flow through the valve body, the fluid flow path includes afirst portion having a first centerline and a second portion having asecond centerline, wherein the first centerline is offset from thesecond centerline.
 3. The valve assembly of claim 1, wherein thethrough-passage includes a first opening on a first side of the valveplug, a second opening on a second side of the valve plug, and a rampedsurface extending at least partially between the first opening and thesecond opening.
 4. The valve assembly of claim 3, wherein the firstopening exhibits a semicircular geometry, and wherein the second openingexhibits a semicircular geometry.
 5. The valve assembly of claim 1,wherein the valve plug forms a seal with the valve body along a proximalside of the valve plug when the valve plug is in a closed position. 6.The valve assembly of claim 1, further comprising at least one backflowprevention device disposed in the fluid flow path.
 7. The valve assemblyof claim 6, wherein the at least one backflow prevention device ispositioned between the valve plug and the inlet of the valve body. 8.The valve assembly of claim 6, wherein the at least one backflowprevention device is positioned between the valve plug and the outlet ofthe valve body.
 9. The valve assembly of claim 6, wherein the at leastone backflow prevention device comprises a flexible and resilientmaterial, and is movable relative to the valve body to control fluidflow through the fluid flow path independent of operation of the valveplug.
 10. A valve assembly for a dental suction system, comprising: avalve body having an inlet, an outlet and a fluid flow path extendingbetween the inlet and the outlet; a valve plug positioned at leastpartially within the valve body, the valve plug including athrough-passage, the valve body being displaceable relative to the valvebody to selectively alter a flow of fluid along the fluid flow path; anda backflow prevention device disposed in the fluid flow path between thevalve plug and the inlet of the valve body or between the valve plug andthe outlet of the valve body, the backflow prevention device beingmovable between open and closed positions to control fluid flow throughthe fluid flow path independent of operation of the valve plug.
 11. Thevalve assembly of claim 10, wherein the backflow prevention deviceincludes a resilient, flexible member having a peripheral portion fixedrelative to the valve body.
 12. The valve assembly of claim 10, whereinthe fluid flow path is configured such that the fluid flow path includesa first portion having a first centerline distal of the valve plug and asecond portion having a second centerline as proximal of the valve plug,the first centerline being offset from the second centerline.
 13. Thevalve assembly of claim 10, wherein the valve plug is rotatable betweenopen and closed positions.
 14. The valve assembly of claim 10, whereinthe valve plug sealingly engages the valve body when the valve plug isin a closed position to block fluid flow through the fluid flow path.15. A valve assembly for a dental suction system, comprising: a firstvalve body having a first inlet, a first outlet, and a first fluid flowpath extending between the first inlet and the first outlet; a secondvalve body having a second inlet, a second outlet, and a second fluidflow path extending between the second inlet and the second outlet; abackflow prevention device captured between the first and second valvebodies, the backflow prevention device being movable to control fluidflow along at least one of the first and second fluid flow paths; avalve plug positioned at least partially within the first valve body,the valve plug including a through-passage, the valve body beingdisplaceable relative to the valve body to selectively alter a flow offluid along at least one of the first and second fluid flow paths. 16.The valve assembly of claim 15, wherein the first fluid flow pathincludes a first portion having a first centerline distal of the valveplug and the second fluid flow path includes a second portion having asecond centerline proximal of the valve plug, the first centerline beingoffset from the second centerline.
 17. The valve assembly of claim 15,wherein the backflow prevention device is positioned between the valveplug and the first inlet.
 18. The valve assembly of claim 15, whereinthe backflow prevention device is positioned between the valve plug andthe first outlet.
 19. The valve assembly of claim 15, wherein at leastone of the first and second valve bodies includes an alignment featureconfigured to align the first valve body relative to the second valvebody in a predetermined rotated position.
 20. The valve assembly ofclaim 15, wherein the valve plug forms a seal with the second valve bodyalong a proximal side of the valve plug when the valve plug is in aclosed position.